scholarly journals Engineering of the band gap and optical properties of thin films of yttrium hydride

2014 ◽  
Vol 105 (3) ◽  
pp. 031910 ◽  
Author(s):  
Chang Chuan You ◽  
Trygve Mongstad ◽  
Jan Petter Maehlen ◽  
Smagul Karazhanov
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Yttrium Hydride

Deposition time dependent study of structural and optical properties of PbS thin films grown by CBD method

2020 ◽  
Vol 13 ◽  
Author(s):  
Minakshi Chaudhary ◽  
Yogesh Hase ◽  
Ashwini Punde ◽  
Pratibha Shinde ◽  
Ashish Waghmare ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Deposition Time ◽  
Secondary Growth ◽  
Cost Effective ◽  
Xrd Analysis ◽  
Structural Morphology ◽  
Glass Substrates ◽  
Cbd Method

: Thin films of PbS were prepared onto glass substrates by using a simple and cost effective CBD method. Influence of deposition time on structural, morphology and optical properties have been investigated systematically. The XRD analysis revealed that PbS films are polycrystalline with preferred orientation in (200) direction. Enhancement in crystallinity and PbS crystallite size has been observed with increase in deposition time. Formation of single phase PbS thin films has been further confirmed by Raman spectroscopy. The surface morphology analysis revealed the formation of prismatic and pebble-like PbS particles and with increase in deposition time these PbS particles are separated from each other without secondary growth. The data obtained from the EDX spectra shows the formation of high-quality but slightly sulfur rich PbS thin films over the entire range of deposition time studied. All films show increase in absorption with increase in deposition time and a strong absorption in the visible and sub-band gap regime of NIR range of the spectrum with red shift in band edge. The optical band gap shows decreasing trend, as deposition time increases but it is higher than the band gap of bulk PbS.

Optical Properties of Alq3/TiO2 BDR Structure Processed by Spin Coating Technique

MRS Advances ◽  
2019 ◽  
Vol 4 (11-12) ◽  
pp. 661-666
Author(s):  
L. Ajith DeSilva ◽  
Sarahn Nazaret ◽  
A. G. U. Perera ◽  
T. M. W. J. Bandara
Keyword(s):  
Thin Films ◽  
Titanium Dioxide ◽  
Optical Properties ◽  
Band Gap ◽  
Spin Coating ◽  
Light Emission ◽  
Wide Band ◽  
Bragg Reflector ◽  
Distributed Bragg Reflector ◽  
Pl Quenching

ABSTRACTOne-dimensional hybrid Distributed Bragg Reflector (DBR) is constructed using Tris (8-hydroxy) quinoline aluminum (Alq3) molecules and Titanium dioxide (TiO2) nanoparticles via spin coating process. Light emission from thin films of low molecular weight organic semiconductor of Alq3 is dominated by excitons. This material has been widely used as a superior emitter for organic light emitting diodes. Titanium dioxide (TiO2) is an inorganic semiconductor with a high band gap. Photoluminescence (PL) of thin films of Alq3 showed a broad PL peak at 530 nm. In DBR structures, PL quenching is observed but there is no shift in the PL peak of the Alq3. The PL quenching is tentatively attributed to energy transfer via sensitization to wide band gap TiO2 layers. A simple excitonic model is suggested to explain the observation. Fabrication process and optical properties of the structure are presented.

Optical Properties of NiO Thin Films: A Potential Material for Optoelectronic Devices

2012 ◽  
Vol 488-489 ◽  
pp. 103-108 ◽  
Author(s):  
Manisha Tyagi ◽  
Monika Tomar ◽  
Vinay Gupta
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Substrate Temperature ◽  
Band Gap ◽  
Urbach Energy ◽  
Rf Sputtering ◽  
Blue Shift ◽  
Structural Disorder ◽  
Near Ir

The influence of substrate temperature on the UV-Visible-near-IR optical properties, namely the band gap, the Urbach energy and the refractive index of NiO thin films deposited by RF sputtering has been investigated. The optical band gap of thin films showed the blue-shift in the transmission spectra with increase in the substrate temperature which is related to variation in carrier concentration of the deposited films. Urbach energy (EU) values indicate that the films deposited at 400 oC substrate temperature show least structural disorder. The refractive index of the films is found to decrease continuously with increase in the substrate temperature at all photon energies in the visible and near-IR region, and is attributed to the decreasing packing density of the films. Introduction

scholarly journals Optical properties of CuSe thin films - band gap determination

2017 ◽  
Vol 49 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Milica Petrovic ◽  
Martina Gilic ◽  
Jovana Cirkovic ◽  
Maja Romcevic ◽  
Nebojsa Romcevic ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Room Temperature ◽  
Nir Spectroscopy ◽  
Copper Selenide ◽  
Photoluminescence Spectra ◽  
Indirect Transition ◽  
Direct Transition ◽  
Scanning Electron

Copper selenide thin films of three different thicknesses have been prepared by vacuum evaporation method on a glass substrate at room temperature. The optical properties of the films were investigated by UV-VIS-NIR spectroscopy and photoluminescence spectroscopy. Surface morphology was investigated by field-emission scanning electron microscopy. Copper selenide exhibits both direct and indirect transitions. The band gap for direct transition is found to be ~2.7 eV and that for indirect transition it is ~1.70 eV. Photoluminescence spectra of copper selenide thin films have also been analyzed, which show emission peaks at 530, 550, and 760 nm. The latter corresponds to indirect transition in investigated material.

scholarly journals Effect of Doping Concentration on the Optical Properties of Indium-Doped Gallium Arsenide Thin FILMS

2016 ◽  
Vol 40 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Md Saiful Islam ◽  
Chitra Das ◽  
Mehnaz Sharmin ◽  
Kazi Md Amzad Hussain ◽  
Shamima Choudhury
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Doping Concentration ◽  
High Vacuum ◽  
Band Gap Energy ◽  
Crystal Thickness ◽  
Thermal Evaporation Method ◽  
Gap Energy ◽  
Indium Doping

Effects of indium doping (concentration 0.2, 0.3 and 0.4%) on the optical properties of GaAs thin films were studied. Thin films of 600 nm were grown onto chemically and ultrasonically cleaned glass substrate by thermal evaporation method in high vacuum (~10-4 Pa) at 50°C fixed substrate temperature. The samples were annealed for 15 minutes at a fixed temperature of 200°C. The thicknesses of films were being measured in situ by a quartz crystal thickness monitor during deposition. The transmittance and reflectance data were found using UV-VIS-NIR spectrophotometer in the photon wavelength range of 310 ~ 2500 nm. These data were utilized to compute the absorption coefficient, refractive index, extinction co-efficient and band gap energy of the studied films. Here transmittance was found 78 for 0.2% indium doping concentration. The band gap energy decreased with the increase of doping concentration.Journal of Bangladesh Academy of Sciences, Vol. 40, No. 2, 179-186, 2016

Properties of CdS Thin Films Grown by Chemical Bath Deposition as a Function of Bath Temperature

2009 ◽  
Vol 609 ◽  
pp. 243-247 ◽  
Author(s):  
H. Moualkia ◽  
S. Hariech ◽  
M.S. Aida
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Chemical Bath Deposition ◽  
Bath Temperature ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Cds Thin Films ◽  
Direct Band

The present work deals with the preparation and characterization of cadmium sulfur (CdS) thin films. These films are prepared by chemical bath deposition on the well cleaned glass substrates. The thickness of the samples was measured by using profilometer DEKTAK, structural and optical properties were studied by X-ray diffraction analysis, and UV-visible spectrophotometry. The optical properties of the films have been investigated as a function of temperature. The band gap energy and Urbach energy were also investigated as a function of temperature. From the transmittance data analysis the direct band gap ranges from 2.21 eV to 2.34 eV. A dependence of band gap on temperature has been observed and the possible raisons are discussed. Transmission spectra indicates a high transmission coefficient (75 %). Structural analysis revealed that the films showed cubic structure, and the crystallite size decreased at a higher deposition temperature.

Structural and optical properties of delafossite-type CuAlO2 thin films prepared by RF reactive sputtering

2005 ◽  
Vol 905 ◽  
Author(s):  
B. Yang ◽  
Y. M. Lu ◽  
C. Neumann ◽  
A. Polity ◽  
C. Z. Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Reactive Sputtering ◽  
Wavelength Dependence ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Deposition Parameters ◽  
Delafossite Structure ◽  
Average Transmittance

AbstractDelafossite-type CuAlO2 thin films have been deposited by radio frequency (RF) reactive sputtering on sapphire using a CuAlO2 ceramic target. A study of structural and optical properties was performed on films of varying deposition parameters such as substrate temperature and oxygen partial pressure and also post annealing. The crystalline phase in the films was identified to be the delafossite structure by x-ray diffraction. The optical properties, such as the wavelength dependence of the transmittance and the band gap, were determined. The average transmittance is 80% in the wavelength range of 400-1500 nm and the band gap is 3.81 eV.

The Optical Properties and Band Gap Energy of Nanocrystalline La0.4Sr0.6TiO3 Thin Films

2005 ◽  
Vol 88 (5) ◽  
pp. 1186-1189 ◽  
Author(s):  
Toshio Suzuki ◽  
Piotr Jasinski ◽  
Vladimir Petrovsky ◽  
Harlan U. Anderson
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Band Gap Energy ◽  
Gap Energy

Effects of Nitrogen Doping on Optical Properties of Tungsten Oxide Thin Films

2012 ◽  
Vol 616-618 ◽  
pp. 1773-1777
Author(s):  
Xi Lian Sun ◽  
Hong Tao Cao
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Tungsten Oxide ◽  
Nitrogen Doping ◽  
Optical Band Gap ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Tungsten Oxide Thin Films

In depositing nitrogen doped tungsten oxide thin films by using reactive dc pulsed magnetron sputtering process, nitrous oxide gas (N2O) was employed instead of nitrogen (N2) as the nitrogen dopant source. The nitrogen doping effect on the structural and optical properties of WO3 thin films was investigated by X-ray diffraction, transmission electron microscopy and UV-Vis spectroscopy. The thickness, refractive index and optical band gap energy of these films have been determined by analyzing the SE spectra using parameterized dispersion model. Morphological images reveal that the films are characterized by a hybrid structure comprising nanoparticles embeded in amorphous matrix and open channels between the agglomerated nanoparticles. Increasing nitrogen doping concentration is found to decrease the optical band gap energy and the refractive index. The reduced band gaps are associated with the N 2p orbital in the N-doped tungsten oxide films.

Optical Properties of PZT, PLZT, and PNZT Thin Films

1991 ◽  
Vol 243 ◽  
Author(s):  
Chien H. Peng ◽  
Jhing-Fang Chang ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Pzt Films ◽  
Direct Band ◽  
Band Transition ◽  
La Doped

AbstractOptical properties were investigated for undoped, La-doped, and Nd-doped Pb(ZrxTi1-x)O3 thin films deposited on sapphire substrates by metalorganic decomposition (MOD) process. Refractive index and extinction coefficient of these films were calculated from transmission spectra in the wavelength range of 300 to 2000 nm. The packing densities of these films were calculated from the refractive index data by using the effective medium approximation. Band gap energies of these films were also reported under the assumption of direct band-to-band transition. The refractive index and band gap energy of PZT films showed a linear dependence on Zr/Ti ratio. The refractive index decreased, while the band gap energy increased with increasing zirconium content. It was also found that both La-doped and Nd-doped PZT films had higher refractive indices than those of undoped PZT films with the same Zr/Ti ratio (50/50).

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